Root locus techniques in the log s plane for design and analysis of feedback control systems.

Abstract

Root locus plots in the s plane are practically limited to a span of two decades. In problems where some poles are very close to the origin, while other poles or zeros are at very large values of s, sufficient resolution of the locus may not be available in two decades of the s plane. However, root loci can be plotted in the In s plane using as many decades as desired (and whichever are desired). Electro-Scientific Industries Corporation manufactures an analog computer, THE ESIAC, which constructs root locus plots in the In s plane. This paper presents a mathematical analysis of the In s plane, a simple method of plotting root loci in the In s plane, and several practical examples demonstrating the technique. Construction of root loci by this method requires the use of one template.